Gallopingcamel

@todofwar "I thought one of the reasons they choose against LFTR in the olden days was it wasn't good for generating material for bombs. Could be wrong about that though." Sorensen says that the LFTR will have a positive effect on "Proliferation". He points out that the plutonium produced by LFTRs is mostly Pu238 which is not fissile and is the most valuable element on earth (~$8,000,000 per kilogram). Sorensen explains that LFTRs breed fissile U233 which can easily be extracted from the reactor salts by bubbling Fluorine through the FLIBE. This U233 would be a superb material for making bombs but for the fact that it is contaminated with U232 which emits energetic gamma rays that are easy to detect. These gamma rays destroy sensitive electronics based on semiconductors. What Sorensen does not mention is that one can get weapons grade U233 from LFTRs using (inexpensive) chemical separation. LFTRs are superb reactors for creating nuclear bombs. LFTRs create Protoactinium 233 which can be chemically separated from the FLIBE. Pa233 converts to U233 with a half life of 27 days. While I like Sorensen, I would like him much more if he did not try to sweep this problem under the rug.

@RainDreamer, "So how practical is this for space use?" The first MSR was intended to power an aeroplane so it had to be small and light. Sorensen worked at NASA designing reactors for use in space or on the surface of the Moon. He picked the LFTR and IMHO this still looks like the best choice when it comes to MW/kg. Can you imagine what it would take to build a BWR on the Moon? In contrast a 100 MWe LFTR would weigh less than 20 tonnes.

@cantab My degree is M.A. (Cantab). I studied at Pembroke college and was able to walk to work at the Cavendish laboratory. The Cavendish has relocated but the plaque showing where J.J Thomson discovered the electron in 1899 is still there.

I may be pushing my luck here. On Monday I emulated Dorothy and got "Behind the Curtain" at the Kennedy Space Center. I visited the control room in Hangar AE where the managers oversee most of the launches. This stuff is beyond cool! Recently Stephen Hawking has been talking about interstellar space travel using micro robots. Let's hope we will do much better: https://diggingintheclay.wordpress.com/2013/06/17/bussard-revisited/

This is my first post here. I am a physicist/engineer who helped build the world's brightest gamma ray source. While I am a trained "Radiation Worker" my field is electro-optics rather than nuclear physics so my opinions on nuclear reactors are those of an "Informed Amateur". I like MSRs (Molten Salt Reactors) in general and LFTRs (Liquid Fluoride Thorium Reactors) in particular. Here is an update on that video you posted: One of the engineering problems with LFTRs is finding materials that can withstand high temperatures and high radiation flux. Hastelloy-N is the best material known for this purpose but it does not have the needed life expectancy in a high radiation environment. This video explains how graphite can be used as a moderator and as a means of protecting the Hastelloy from radiation damage. While I am a fan of the LFTR the concept is "Vaporware" until someone builds one. In that respect it is no better than Andrea Rossi's E-Cat. I am highly sceptical of LENR (Cold Fusion?) in general and scam artist Andrea Rossi in particular. Even so there are Nobel prize winners who take Rossi seriously: While I respect Brian Josephson as a physicist and a fellow Welshman I am not convinced by his arguments.